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Número de publicaciónUS5057105 A
Tipo de publicaciónConcesión
Número de solicitudUS 07/571,212
Fecha de publicación15 Oct 1991
Fecha de presentación23 Ago 1990
Fecha de prioridad28 Ago 1989
TarifaPagadas
También publicado comoCA2065261A1, CA2065261C, DE69029393D1, DE69029393T2, EP0489814A1, EP0489814A4, EP0489814B1, USRE35330, WO1991003208A1
Número de publicación07571212, 571212, US 5057105 A, US 5057105A, US-A-5057105, US5057105 A, US5057105A
InventoresDavid G. Malone, James L. Vacek, G. Scott Smith
Cesionario originalThe University Of Kansas Med Center
Exportar citaBiBTeX, EndNote, RefMan
Enlaces externos: USPTO, Cesión de USPTO, Espacenet
Hot tip catheter assembly
US 5057105 A
Resumen
A hot tip catheter assembly is disclosed which resolves atherosclerotic plaque buildup in vivo. The catheter has a heater, a cap, a thermocouple, power leads, thermocouple leads, and a central distal lumen to position the catheter within the artery. The catheter tip has a thin, non-adhesive coating of a hard, heat-conducting material. The thermocouple is used to continuously evaluate the temperature at the tip of the catheter, and the temperature is then regulated by a computer-controlled feedback system. The catheter can completely melt the buildup without damage to the artery by direct contact with the plaque, without use of balloon catheter angioplasty.
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Reclamaciones(10)
We claim:
1. A method of applying heat to the interior of a vessel in vivo, said method comprising the steps of:
inserting an electrically heatable, voltage responsive, hot tip catheter assembly having a catheter tip into the vessel;
positioning said catheter tip in the vicinity of the vessel interior to be heated;
heating said catheter tip;
monitoring the temperature of said catheter tip;
comparing said temperature with a set point temperature representative of a predetermined temperature set point for said catheter tip;
determining the deviation between tip temperature and set point temperature;
determining the rate of change of said deviation; and
applying a voltage to said catheter tip in accordance with both said deviation and said rate of change of said deviation in order to control the temperature of said catheter tip at said set point temperature.
2. The method as set forth in claim 1, further including the step of applying said voltage to at least one avalanche diode as part of said catheter assembly for heating thereof.
3. The method as set forth in claim 2, further including the step of applying said voltage to three avalanche diodes connected in series.
4. The method as set forth in claim 1, further including the step of providing a thermocouple for monitoring said tip temperature.
5. The method as set forth in claim 1, further including the step of providing a microcomputer as means for performing said monitoring, comparing and determining steps.
6. An apparatus for applying heat to the interior of a vessel in vivo, said apparatus comprising:
an electrically heatable, voltage responsive, hot tip catheter assembly having a catheter tip configured for insertion into the vessel and for positioning of said catheter tip in the vicinity of the vessel interior to be heated, said assembly including means for heating said catheter tip; and
heat control means operably coupled with said catheter assembly for controlably heating said catheter tip, said control means including
means for monitoring the temperature of said catheter tip;
means for comparing said temperature with a set point temperature representative of a predetermined temperature set point for said catheter tip;
means for determining the deviation between tip temperature and set point temperature and for determining the rate of change of said deviation; and
means for applying a voltage to said catheter tip in accordance with both said deviation and said rate of change of said deviation in order to control the temperature of said catheter tip at said set point temperature.
7. The apparatus as set forth in claim 6, said catheter tip including at least one avalanche diode responsive to the application of said voltage for producing heat.
8. The apparatus as set forth in claim 7, said catheter tip including three of said avalanche diodes connected in series.
9. The apparatus as set forth in claim 6, said temperature monitoring means including a thermocouple.
10. The apparatus as set forth in claim 6, said control means including a microcomputer.
Descripción

This application is a continuation-in-part of Ser. No. 07/399,773; filed Aug. 28, 1989, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is concerned with a system for resolving atherosclerotic plaque build-up in vivo. More particularly, the invention hereof involves a hot tip catheter assembly and technique for temperature control removal of arterial plaque.

2. Description of the Prior Art

Coronary artery disease occurs when arteries which supply oxygen-rich blood to the heart are narrowed (partially blocked) by a build up of fatty and fibrous substances known as atherosclerotic plaque. Arteries are composed of three layers. The innermost layer is the intima, the middle layer is the muscularis, and the outermost layer is the adventitia. The atherosclerotic plaque is deposited directly underneath the intima. The plaque can build up on coronary as well as peripheral arteries.

Various conventional methods are currently used for opening arteries which are constricted by atherosclerotic plaque, and several accomplish this by compression or removal of the plaque which results in residual sites of injury which predisposes to recurrent occlusion. These methods are generally seen as alternatives to coronary artery bypass procedures which are expensive and traumatic in terms of patient morbidity. One of the most commonly used methods is percutaneous transluminal balloon dilatation (angioplasty) which reduces the blockage by dilatation of the lumen of the artery, which reforms and compresses atherosclerotic plaque. Another method is the use of implantable stents in cases where the arteries have failed to remain patent after balloon angioplasty. Atherectomy devices are used to physically cut through the atherosclerotic plaque and remove it from the artery. Laser angioplasty is also available wherein a channel is created through the arteries by heating or melting the plaque using a laser. Other non-laser devices have been developed which also soften or melt plaque using various thermal means.

Balloon angioplasty is not always effective, however, especially when the plaque has hardened due to the presence of a high concentration of calcium in the plaque. Further, if the lumen of the artery is mostly or completely constricted, balloon angioplasty is not feasible as the balloon catheter cannot be placed within the opening of the blockage.

The angioplasty devices which are currently used to soften or melt the atherosclerotic plaque have several drawbacks. These devices often cause damage to the interior walls of the arteries by misdirecting the thermal energy used, focusing it on the arterial wall rather than the plaque. Damage can also be caused by a failure to accurately and effectively regulate and maintain the temperature of the thermal energy used. If the temperature gets too high, a hole can be burned through the wall of the artery. No effective system for precisely regulating temperature at the tip of a thermal ablating device are available.

Furthermore, conventional thermal devices often have problems being cooled by the surrounding tissue with sufficient speed, generally due to the relatively high thermal mass of the catheters. Current leakage has been another problem with prior thermal devices, which may result in lethal cardiac arrhythmias. An additional problem with prior thermal devices is the formation of char from thermally damaged debris on the top of the heated cap, which may cause adhesion of the catheter tip to the vessel wall.

SUMMARY OF THE INVENTION

In response to these problems, the device of the present invention provides a catheter having a specific heating element, a heat-transferring metallic cap, a thermocouple, power leads, thermocouple leads, a central distal lumen for positioning the tip of the catheter over a guide wire and/or injecting contrast dye and/or performing pressure measurements, and a computer-based control system. The catheter tip can be positioned over a guide wire which has been placed within the artery proximate to the atherosclerotic plaque blockage.

The heater element is composed of a semiconductor, which must be modified to fit within the tight confines of a coronary artery. While it can be made using any of several suitable semiconductors, in one embodiment the semiconductor is a package containing three avalanche diodes connected in series.

The control system is comprised of specifically designed and integrated computer hardware and software. The goal of the control system is to keep the catheter tip within 10° C. of the desired temperature, and below 180° C. The thermocouple is used to continuously evaluate the temperature at the catheter tip, and the tip is brought to its proper temperature by the computer-controlled feedback system which determines the amount of voltage which must be provided by the power supply to the catheter tip. In this manner, the proper catheter tip temperature is constantly maintained in order to minimize the risk of any damage to the muscularis while preferentially ablating the atherosclerotic elements of the plaque.

The catheter tip, when properly positioned within the artery, melts the atherosclerotic plaque by direct conduction of heat. The plaque can be melted so completely that there is no need to follow this procedure with balloon catheter angioplasty. The site of thermal ablation is less likely to result in reocclusion rather than if other methods which leave a focus of arterial wall injury are utilized. The catheter tip is coated with a thin, heat-conducting substance such as Teflon, a silicon compound, or a ceramic substance which promotes free movement of the catheter within the vessel and avoids build-up of char on the catheter tip and adhesion of the heating element of the vessel.

Accordingly, it is the primary object of the present invention to provide a device to be used inside of an artery for removing obstructions therein, such as atherosclerotic plaque, without regard to the degree of blockage existing.

It is another object of the invention to provide a device as described above, wherein the atherosclerotic plaque in arteries is removed by melting.

It is a further object of the present invention to provide a device as described above, wherein the atherosclerotic plaque can be melted with a relatively low rate of perforation of the walls of the arteries.

It is yet another object of the present invention to provide a device as described above, wherein the temperature of the tip of the catheter is continuously monitored and regulated and can be maintained at the exact temperature necessary for the angioplasty process.

It is still another object of the present invention to provide a device as described above, wherein the monitoring and regulating of the catheter tip temperature is controlled by a thermocouple and a minicomputer feedback control system.

It is another object of the present invention to provide a device as described above, wherein the catheter tip is coated with a thin, hard conductive, but non-adhesive material to avoid debris build-up on the catheter tip and promote catheter mobility within the vessel.

It is a still further object of the present invention to provide a device as described above, wherein the catheter tip is rapidly and efficiently heated by using avalanche or zener diodes.

It is a further object of the present invention to provide a device as described above, wherein the catheter assembly is inexpensive, easy to work with, sturdy and uses materials readily available.

It is still another object of the present invention to provide a device as described above, wherein the minicomputer feedback system provides for automatic shut-off at the tip in any emergent situation.

It is yet a further object of the present invention to provide a device as described above, wherein a minimal amount of current leakage occurs.

Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings, wherein is set forth by way of illustration and example, an embodiment of this invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the hot tip catheter assembly, the minicomputer control system not being shown.

FIG. 2 is a perspective view depicting the catheter of FIG. 1 positioned within a coronary artery having atherosclerotic plaque buildup, with a portion of the artery broken away to show the catheter tip approaching the blockage, the broken lines representing the catheter body.

FIG. 3 is an enlarged perspective view of the catheter tip being led by the guide wire within an artery which is shown in cross section, proximate to the build-up of atherosclerotic plaque.

FIG. 4 is an enlarged cross-sectional view of the catheter as in FIG. 3, with a majority of the atherosclerotic plaque resolved.

FIG. 5 is a schematic diagram of the power supply and microcomputer control assembly connected to the hot tip catheter assembly.

FIG. 6 is a flow diagram of the microcomputer temperature control assembly which regulates the hot tip catheter.

FIG. 7 is a computer program flowchart for operating the microcomputer of FIG. 5 in accordance with the flow diagram of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 depicts a hot tip catheter assembly, generally referred to as 8, having a body 10 and a catheter tip 15 which is composed of a heater element 12 and a catheter cap 14. The cap 14 is preferably elliptical in shape. The tip 15 is adjacent a distal end 52 of the catheter body 10. A central opening or guide wire lumen 17 extends longitudinally throughout the catheter body 10, and the catheter tip 15. A guide wire port 18 extends from a proximal end 50 of the catheter 10 and is designed to receive a guide wire 16. The guide wire 16 extends from the port 18 through the central opening 17 beyond the tip 15. Power leads 22a and 22b extend longitudinally through a fitting 24 and the body 10, and are connected to the heater element 12. In a similar manner, thermocouple leads 20 are connected to the heating element 12 and extend longitudinally through the body 10 and the fitting 24. A catheter sheath 11 extends from the fitting 24 to the cap 14. A thin layer of non-adhesive coating surrounds the catheter sheath 11 from the cap 14 to the proximal end 50, and is depicted in FIG. 4.

FIG. 2 shows the catheter assembly 8 positioned within a coronary artery 28 proximate to a buildup of atherosclerotic plaque 30. The guide wire 16 extends beyond the catheter cap 14 and through the plaque blockage 30. The catheter and guide wire assembly 16 may be positioned at any of several points in this vessel 28 or other coronary arteries 28a and 28b or the branches thereof depending on the site of atherosclerotic obstruction.

FIGS. 3 and 4 show an enlarged detail view of the catheter tip 15 positioned within an artery proximate to the atherosclerotic plaque buildup 30. FIG. 4 shows the buildup 30 after it has been resolved by the angioplasty catheter assembly 8. The three layers of the artery wall are depicted and are the intima 32, the muscularis 34, and the adventitia 36.

Referring again to FIG. 4, the heater element 12 is comprised, in one embodiment, of triple-stacked avalanche or zener diodes 38a, 38b and 38c. The cap 14 is connected to end 37 of the diode package 38. The catheter sheath 11 extends from the cap 14 to the proximal end 50 and peripherally surrounds the diode package 38. The non-adhesive coating 25 is a thin, hard conductive material. This material can be any suitable substance, but is preferably Teflon, a silicon compound, or a ceramic material. The guide wire opening 17 extends throughout the cap 14 and the diode package 38. The power leads 22a and 22b are attached to ends 37 and 39, respectively, of the diode package 38, with the positive power lead 22b attached to the cathode 39 of the diode package 38, and the negative power lead 22a attached to the anode 37 of the diode package 38. As seen in FIG. 5, the leads 22a and 22b connects the diode package 38 to a power supply 44. Thermocouple leads 20 connect end 39 of the diode package 38 with the temperature compensation circuit 48.

Referring now to FIG. 5, the minicomputer feedback system is composed of the temperature compensation circuit 48 (optional) connected to the catheter tip 15 by the thermocouple leads 20, a multimeter 46, an interface bus 42, a minicomputer 40, and the power supply 44 which is connected to the catheter tip 15 by the power leads 22a and 22b.

As discussed above, the heater element 12 of the preferred embodiment is composed of a semiconductor package 38 of three avalanche or zener diodes 38a, 38b and 38c in series. A diode is a single P-layer/N-layer interface. The N-layer contains minute amounts of electron rich materials such as phosphorus, arsenic, antimony or bismuth. The P-layer contains minute amounts of materials with only three electrons in the valence band such as boron, aluminum or gallium. When P-type and N-type materials are placed together forming a junction, electrons from the negative region diffuse across the junction into the P region. In a similar fashion, "holes" from the P region diffuse along the concentration gradient from the P region to the N region. This sets up an electric field with a barrier voltage across the junction preventing any further diffusion across the junction in the equilibrium state. An external electric field can be applied to the junction by applying an external voltage. This external voltage can have two polarities. If the positive external voltage is applied to the P-type material and the negative voltage to the N-type material, flow of electrons will occur from the negative to the positive material. As conventional current flows uses hole conduction, the conventional current flows in the opposite direction of electron flow. With current flow from the P-type layer to the N-type layer material as above, the junction is in the forward biased condition and the barrier voltage is lowered.

If the junction is reverse biased with the positive exterior voltage applied to the N-type material and the negative voltage applied to the P-P-type material, the external applied voltage is added to the internal barrier voltage. This requires more energetic electrons to cross the heightened energy barrier in the reverse biased case. Quantum mechanics show the existence of a small population of electrons with sufficient energy to cross the energy gap from the P to the N direction. This is called Is, the saturation current, and it is a small negative current. If a sufficiently large reverse biasing voltage is applied it creates a large electric field across the junction. As an electron with sufficient energy to bridge the gap enters from the anode it is accelerated by the electric field in the junction, thereby gaining more energy. Invariably this electron crossing the junction collides with other bound electrons in the lattice of the junction. If the collision is energetic enough it will dislodge other electrons from the lattice and these dislodged electrons will also be accelerated by the electric field and will collide with other electrons bound to the lattice causing large reverse currents known as breakdown in the avalanche fashion. The large reverse voltage needed to cause this event is called the avalanche breakdown voltage. Another phenomenon called zener breakdown also occurs.

In a simplified fashion, zener breakdown occurs when an electron in the P-layer side with energy below that needed to cross the junctional energy barrier appears on the N-layer side This is called "tunneling", as it appears as if the electron has tunneled under the energy gap, and it results in a negative current called Iz. Thus, the breakdown voltage for any diode is either the zener or the avalanche breakdown voltage and the breakdown current is composed of both the zener and avalanche current. If voltages larger than the avalanche and zener breakdown voltages are applied to the junction, an increased amount of heat is generated. This heat generation causes the thermal generation of hole electron pairs far in excess of that caused by doping the semiconductors with P and N-type material, and the semiconductor acts as if it were pure silicon.

The heater element 12 of the catheter assembly 8 uses a diode package 38 of three 68 volt avalanche diodes 38a, 38b and 38c connected in series. These diodes 38a, 38b and 38c are all reverse biased and the electric field of the reverse biased junctions adds to the resistance of the diode package 38. At the avalanche breakdown voltage the device behaves as a conventional diode. However, when a larger voltage is applied and the junctions are heated sufficiently by the external voltage, the overwhelming majority of hole-electron pairs are from thermal generation. At this point, the semiconductor package 38 is no longer behaving as three diodes in series, but rather as one single piece of pure silicon. Therefore, the use of avalanche diodes is not essential to the success of the catheter assembly 8, but it does provide more rapid heating. Similarly, although the temperature of avalanche diodes can generally be predicted by their current-voltage characteristics, it is not the case in this invention when the junction is at high temperatures and the diodes are not behaving as conventional diodes, thus necessitating the use of a temperature measuring device in the catheter tip 15, which is composed of the thermocouple leads 20 and the temperature compensation circuit 48.

In this embodiment, the positive power lead 22b is welded with silver or other metals to the cathode 39 of the diode package 38, and the negative power leads 22a is welded to the anode 37 of the diode package 38. The cathode 39 of the diode 38 also has type J thermocouple leads 20 welded to it. The positive power leads 22b/cathode 39/thermocouple lead 20 package is bonded with high temperature silicon adhesive into the distal end 52 of the catheter sheath 11. A silver, stainless steel or brass, elliptically shaped cap 14 with a guide wire opening 17 is welded to the negative power lead 22a/anode 37 of the diode package 38 and is coated with a layer of material having thermal and electrical characteristics similar to ceramic. The catheter sheath 11 has four lumens, two lumens contain the power leads 22a and 22b, one lumen contains a single thermocouple lead 20, the other thermocouple lead passes with the low voltage power lead, and the last lumen contains is the central guide wire opening 17 for the guide wire 16 and contrast dye. Opening 17 can also be used for a saline solution when such is needed to cool the catheter tip 15.

The control segment of the system is composed of hardware and software. The power supply 44, multimeter 46, and interface card 42 are all commercially available devices. These components together with a computer 40 such as the IBM compatible computer of the preferred embodiment form the hardware segment of the control system for the catheter assembly 8. The thermocouple 20 and multimeter 46 measure catheter tip 15 temperature, and the programmable power supply 44 provides the energy needed to heat the tip 15. These devices are connected to the microcomputer 40 by an interface bus 42, and the events of the system 8 are controlled by a specifically-designed software program. The software catheter assembly 8 models its mathematical and thermal characteristics. The goal of the control system is to keep the catheter tip 15 within 10° C. of the desired temperature and below 180° C. This is accomplished as shown in the flow diagram of FIG. 6, and is described as follows. The operator inputs a desired tip temperature and the system compares the temperature of the catheter tip 15 as measured by the thermocouple 20 to the desired temperature; this difference is called the error temperature. The system continually cycles at a frequency of approximately 200 Hertz. The initial application of energy is then made to the tip 15. The induced temperature of the tip is then measured, and the sampling is made. The software allows the system to continually cycle so as to minimize the rate at which the error temperature is changing, so that the next voltage value to be sent to the catheter tip 15 can be calculated. The key control equation can be derived from several methods. The system can be formally analyzed to evaluate the coefficients in the control equation or the system coefficients can be determined experimentally. This system has been modeled and was found to be a first order system with the following equation.

Temperature=(A*voltage) * (1-exp(-1*t/tau)) where temperature is the tip 15 temperature, A is a coefficient, t is an arbitary time (usually the average cycle time), and tau is the time constant of the system.

The control system equation is based on the error temperature, i.e. the difference between the desired temperature and the actual temperature. When the tip 15 is actually hotter than the desired temperature, the error temperature has a negative value. The equation is as follows:

ET=Desired Temperature-Actual Temperature

where ET is the error temperature. ET is then used to compute a new voltage value to be sent to the catheter tip 15 by the following equation:

V=VO+ET*K1+DET*K2

In this equation V is the value to be sent by the power supply 44 to the catheter tip 15, VO is the voltage value sent to the catheter tip 15 on the lat cycle, ET is error temperature, K1 and K2 are experimentally derived constants, and DET is the first derivative of the error temperature with respect to time.

Proper determination of the coefficients K1 and K2 by iterative, mathematical or combined methods allow the catheter tip 15 temperature to be controlled to a precise level. After this value is calculated, it is sent over the interface bus 42 to the power supply 44 and the power supply 44 sends this voltage to the distal end 52 of the catheter assembly 8. Once the desired tip 15 temperature is achieved, the catheter 8 is moved forward through the build-up. The temperature is continually monitored and regulated in this fashion until the plaque 30 is vaporized.

The software is designed to provide an overdamping function at the tip so no temperature overshoot occurs. The computer 40 also allows for estimation of the energy transferred to the plaque 30 and provides data in the event of muscularis 34 damage so the system can be automatically shut off. The thermal compensation circuit 48 eliminates the need for an ice bath, which has been used in the prior art to provide a reference temperature for the thermocouple.

In use, the catheter body 10 is inserted directly inside an artery 28 following the guide wire 16 until the catheter tip 15 reaches the blockage of atherosclerotic plaque 30. It is essential that this catheter assembly 8 be constructed so that it is capable of miniaturization for use within an artery (1.0-3.5 mm in diameter). Direct current and stable voltage are applied as determined by the minicomputer 40, and the catheter tip 15 is used to thermally ablate vessels by direct contact with the cap 14. The thermocouple evaluates the temperature of the catheter tip 15 and brings it to its proper temperature by a feedback system using the temperature compensation circuit 48 and compute control. Specifically, the measured temperature is fed into a control algorithm which determines the next appropriate voltage to be sent out to the catheter tip 15 so that the proper tip 15 temperature can be maintained at all times. The software also provides fail-safe type parameters such that automatic shut-off at the tip 15 can occur in any emergent situation.

Additionally, the feedback data gives some indication of which layer of the arterial wall the angioplasty is affecting based upon the thermal characteristics of the surrounding tissue. This provides a significantly lower perforation rate than has been found in conventional angioplasty devices. Studies published in the literature show a varying thermal resistance of the three layers of the arterial wall. The muscularis 34 is the layer most resistant to damage by thermal energy. Conversely, atherosclerotic plaque 30 melts at a temperature level lower than that which damages the muscularis 34. The hot tip catheter assembly 8 and its control system take advantage of this natural variation of thermal resistance by maintaining the tip 15 temperature at a level above the needed to melt the plaque 30 but below that which damages the muscularis 34. Thus, the catheter tip 15 is heated to a range of 160° to 180° C. The heat is applied to the plaque 30 for time periods of approximately 30 to 60 seconds in order to resolve the atheromatous buildup. The non-adhesive coating 25 of the tip 15 reduces drag upon the catheter body 10 as it is passed through the vessel and across the area of stenosis. It also inhibits the adhesion of char and tissue debris to the catheter tip 15, which has limited the application of prior thermal angioplasty devices.

The catheter tip 15 has a very low thermal mass, and as it is not heated to an excessive temperature, it does not require complicated cooling mechanisms which have been limitations of prior thermal systems. The tip 15 may be cooled by hypothermic saline which can be injected through the guide wire opening 17, and additionally by losing heat to the surrounding tissues by direct thermal contact. The low thermal mass is also significant in that selective heating of the outer edge of the tip 15 is not necessary, as has been the case in other conventional catheter devices. Further, the catheter tip 15 is designed to be able to remove atherosclerotic plaque buildup 30 and open arteries de novo without the use of a guide wire 16 if a vessel is completely occluded, and can completely open these arteries without need for subsequent balloon angioplasty catheters. The restenosis rate is possibly lessened in this manner.

The hot tip catheter assembly 8 has also taken problems of electrical current into account. In the preferred embodiment, the current flow into the catheter follows a wire to the distal end 52 where it is welded to the semiconductor package 38 itself. The positive power lead 22b is welded completely within the catheter sheath 11 so that the higher voltage is not exposed to any of the tissue. The negative lead 22a is welded to the exterior part of the probe and is coated with a thermally conductive but electrically resistive material. Animal studies conducted with the hot tip catheter assembly 8 revealed no difficulties in that none of the animals suffered any damage from electric shock. Studies were also done in saline to determine the current leakage, and these were all less than 3 milliamperes.

Initial catheter testing has shown the diode package to withstand a maximum temperature of 384° C. on repeated temperature cycles without any failures. Prototype studies done in air showed the catheter could cause cutting of animal protein tissues. These studies were continued using atherosclerotic fresh cadaveric human aorta and they revealed preferential cutting of soft atheromatous plaque with sparing of the muscularis. The experimental results were compared to those published in the literature and revealed comparable degrees of cutting, temperature ranges and power usages. A catheter prototype was then constructed for use in vivo in a rabbit model. This raised the question of arrhythmogenicity from current leakage from the catheter tip. Experiments on the prototype catheters done in saline solution showed a maximum current leakage of 3 milliamperes. Mechanical angioplasty with no heating of the tip was performed during the animal studies and it revealed no plaque removal. In contrast, during in vivo angioplasty of rabbit aorta, iliac, and femoral arteries with the tip temperature at 168° C., angiograms and histologic slides revealed striking plaque removal with no damage to the muscularis. Recent studies with laser type thermal ablation catheters have suggested that mechanical angioplasty caused by direct pressure of the laser was responsible for much of the effect of the device, which resulted in high complication rates. The problem is obviated by a temperature-regulated semiconductor thermal ablation catheter such as is embodied in the present invention.

FIG. 7 is a computer program flowchart 700 illustrating the operation of micro-computer 40 in accordance with the temperature control flow diagram of FIG. 6. The program enters at step 702 at which the set point temperature, that is, desired temperature is entered into microprocessor 40.

The program then moves to step 704 which reads the thermocouple voltage as provided by leads 20 and converts this voltage to an equivalent temperature. Step 706 then calculates the error temperature (ET) as the difference between the set point temperature (ST) and the actual temperature (ACT T) as indicated by the thermocouple voltage.

In step 708, the program calculates the first derivative (D) of the change in the air temperature since the last reading. This is determined by calculating the difference between the error temperature (as calculated in step 706) and the old error temperature (OLD ET) of the previous pass through the program, divided by the elapsed time since the previous calculation.

Step 710 then uses this information to calculate a new output voltage (V) to be supplied by power supply 44 to heater element 12. New output voltage is determined by adding the old output voltage (OLD V), the error temperature times constant (K1), and the derivative times constant (K2). Constants K1 and K2 are selected in an iterative fashion from air and saline tests to determine the desired response characteristics. Small values for K1 and K2 lead to slow, system response times and large values lead to fast response times resulting in overshoot of the set point temperature. The final values for these constants depend upon the responses desired by the attending physician for the particular application.

In step 712, microprocessor 40 prompts power supply 44 to supply an output voltage V as determined in step 710. This step also stores old error temperature and old voltage respectively equal to current error temperature and output voltage for use in the next set of calculations.

Step 714 then asks whether an interrupt or reset signal is being received by microprocessor 40 which occurs, for example, when a new set point temperature is being entered. If the answer in step 714 is no, the program loops back to step 704. If the answer is yes, the program moves to step 716 which sets the output voltage at zero and then loops back to step 702 to receive the new set point temperature.

Those skilled in the art will appreciate from the discussion above that the present invention provides for very precise control of catheter temperature. This is achieved by controlling the voltage transmitted to heater element 12 in a manner which monitors the slope of temperature change in terms of the error deviation. In this way, deleterious overshooting of the set point is eliminated thereby preventing heat damage to vessel walls which has been a problem in the prior art while, at the same time, precisely controlling temperature at the desired set point to ensure maximum effectiveness in removing plaque.

Those skilled in the art will also appreciate that the present invention can also be used as an intravascular cautery device to occlude side branches of a vessel from inside the vessel, and can be configured for use through the ports of conventional fiberoptic endoscopes and bronchoscopies and the like for cauterization of vessels or to thermally coagulate and resect tumors.

It is to be understood that while certain forms of this invention have been illustrated and described, it is not limited thereto, except in so far as such limitations are included in the following claims.

Citas de patentes
Patente citada Fecha de presentación Fecha de publicación Solicitante Título
US4449528 *20 Jul 198122 May 1984University Of WashingtonFast pulse thermal cautery probe and method
US4582057 *21 Nov 198315 Abr 1986Regents Of The University Of WashingtonFast pulse thermal cautery probe
US4654024 *4 Sep 198531 Mar 1987C.R. Bard, Inc.Thermorecanalization catheter and method for use
US4672962 *7 Oct 198516 Jun 1987Cordis CorporationPlaque softening method
US4691703 *25 Abr 19868 Sep 1987Board Of Regents, University Of WashingtonThermal cautery system
US4748979 *13 Abr 19877 Jun 1988Cordis CorporationPlaque resolving device
US4760845 *14 Ene 19872 Ago 1988Hgm Medical Laser Systems, Inc.Laser angioplasty probe
US4860744 *2 Nov 198729 Ago 1989Raj K. AnandThermoelectrically controlled heat medical catheter
US4899741 *11 Abr 198813 Feb 1990Hgm Medical Laser Systems, Inc.Laser heated probe and control system
Citada por
Patente citante Fecha de presentación Fecha de publicación Solicitante Título
US5366443 *9 Oct 199222 Nov 1994Thapliyal And Eggers PartnersMethod and apparatus for advancing catheters through occluded body lumens
US536649022 Dic 199322 Nov 1994Vidamed, Inc.Medical probe device and method
US53706752 Feb 19936 Dic 1994Vidamed, Inc.Medical probe device and method
US5385148 *30 Jul 199331 Ene 1995The Regents Of The University Of CaliforniaCardiac imaging and ablation catheter
US538554414 May 199331 Ene 1995Vidamed, Inc.BPH ablation method and apparatus
US540945319 Ago 199325 Abr 1995Vidamed, Inc.Steerable medical probe with stylets
US5415657 *13 Oct 199216 May 1995Taymor-Luria; HowardPercutaneous vascular sealing method
US542181913 May 19936 Jun 1995Vidamed, Inc.Medical probe device
US543580513 May 199325 Jul 1995Vidamed, Inc.Medical probe device with optical viewing capability
US5437664 *18 Ene 19941 Ago 1995Endovascular, Inc.Apparatus and method for venous ligation
US54566629 May 199410 Oct 1995Edwards; Stuart D.Method for reducing snoring by RF ablation of the uvula
US5456682 *2 Feb 199410 Oct 1995Ep Technologies, Inc.Electrode and associated systems using thermally insulated temperature sensing elements
US547030819 Nov 199328 Nov 1995Vidamed, Inc.Medical probe with biopsy stylet
US547030912 Ene 199428 Nov 1995Vidamed, Inc.Medical ablation apparatus utilizing a heated stylet
US550774430 Abr 199316 Abr 1996Scimed Life Systems, Inc.Apparatus and method for sealing vascular punctures
US551413123 Sep 19947 May 1996Stuart D. EdwardsMethod for the ablation treatment of the uvula
US5520684 *3 Ago 199428 May 1996Imran; Mir A.Transurethral radio frequency apparatus for ablation of the prostate gland and method
US5540681 *10 Ene 199430 Jul 1996Medtronic CardiorhythmMethod and system for radiofrequency ablation of tissue
US554291512 Ene 19946 Ago 1996Vidamed, Inc.Thermal mapping catheter with ultrasound probe
US555411012 Ene 199410 Sep 1996Vidamed, Inc.Medical ablation apparatus
US555637722 Dic 199317 Sep 1996Vidamed, Inc.Medical probe apparatus with laser and/or microwave monolithic integrated circuit probe
US55992947 Oct 19944 Feb 1997Vidamed, Inc.Microwave probe device and method
US55992958 Nov 19954 Feb 1997Vidamed, Inc.Medical probe apparatus with enhanced RF, resistance heating, and microwave ablation capabilities
US560738927 Nov 19954 Mar 1997Vidamed, Inc.Medical probe with biopsy stylet
US563079423 Sep 199420 May 1997Vidamed, Inc.Catheter tip and method of manufacturing
US5658282 *7 Jun 199519 Ago 1997Endovascular, Inc.Apparatus for in situ saphenous vein bypass and less-invasive varicose vein treatment
US567215326 Sep 199430 Sep 1997Vidamed, Inc.Medical probe device and method
US5681282 *11 Abr 199528 Oct 1997Arthrocare CorporationMethods and apparatus for ablation of luminal tissues
US5688266 *3 Oct 199518 Nov 1997Ep Technologies, Inc.Electrode and associated systems using thermally insulated temperature sensing elements
US5688267 *1 May 199518 Nov 1997Ep Technologies, Inc.Systems and methods for sensing multiple temperature conditions during tissue ablation
US5697281 *7 Jun 199516 Dic 1997Arthrocare CorporationSystem and method for electrosurgical cutting and ablation
US5697536 *18 Nov 199616 Dic 1997Arthrocare CorporationSystem and method for electrosurgical cutting and ablation
US5697882 *22 Nov 199516 Dic 1997Arthrocare CorporationSystem and method for electrosurgical cutting and ablation
US5697909 *10 May 199416 Dic 1997Arthrocare CorporationMethods and apparatus for surgical cutting
US5702386 *28 Jun 199630 Dic 1997Ep Technologies, Inc.Non-linear control systems and methods for heating and ablating body tissue
US57207186 Ene 199424 Feb 1998Vidamed, Inc.Medical probe apparatus with enhanced RF, resistance heating, and microwave ablation capabilities
US572071926 Sep 199424 Feb 1998Vidamed, Inc.Ablative catheter with conformable body
US5735846 *1 May 19957 Abr 1998Ep Technologies, Inc.Systems and methods for ablating body tissue using predicted maximum tissue temperature
US5743903 *12 Ago 199628 Abr 1998Ep Technologies, Inc.Cardiac ablation systems and methods using tissue temperature monitoring and control
US5743905 *27 Feb 199628 Abr 1998Target Therapeutics, Inc.Partially insulated occlusion device
US5755715 *3 Jun 199626 May 1998Ep Technologies, Inc.Tissue heating and ablation systems and methods using time-variable set point temperature curves for monitoring and control
US5766153 *5 Dic 199616 Jun 1998Arthrocare CorporationMethods and apparatus for surgical cutting
US5769847 *24 Abr 199623 Jun 1998Ep Technologies, Inc.Systems and methods for controlling tissue ablation using multiple temperature sensing elements
US5810764 *18 Jul 199622 Sep 1998Arthrocare CorporationResecting loop electrode and method for electrosurgical cutting and ablation
US5810802 *24 Ene 199722 Sep 1998E.P. Technologies, Inc.Systems and methods for controlling tissue ablation using multiple temperature sensing elements
US58108106 Jun 199522 Sep 1998Scimed Life Systems, Inc.Apparatus and method for sealing vascular punctures
US5837001 *8 Dic 199517 Nov 1998C. R. BardRadio frequency energy delivery system for multipolar electrode catheters
US5853409 *27 Ene 199729 Dic 1998E.P. Technologies, Inc.Systems and apparatus for sensing temperature in body tissue
US5860951 *22 Nov 199619 Ene 1999Arthrocare CorporationSystems and methods for electrosurgical myocardial revascularization
US5871469 *5 Feb 199716 Feb 1999Arthro Care CorporationSystem and method for electrosurgical cutting and ablation
US5873855 *22 Nov 199623 Feb 1999Arthrocare CorporationSystems and methods for electrosurgical myocardial revascularization
US5888198 *5 Dic 199630 Mar 1999Arthrocare CorporationElectrosurgical system for resection and ablation of tissue in electrically conductive fluids
US5891095 *5 Dic 19966 Abr 1999Arthrocare CorporationElectrosurgical treatment of tissue in electrically conductive fluid
US58953707 Ene 199720 Abr 1999Vidamed, Inc.Medical probe (with stylets) device
US5897552 *4 Sep 199727 Abr 1999Ep Technologies, Inc.Electrode and associated systems using thermally insulated temperature sensing elements
US5931835 *13 Jun 19973 Ago 1999C. R. BardRadio frequency energy delivery system for multipolar electrode catheters
US5935075 *20 Sep 199610 Ago 1999Texas Heart InstituteDetecting thermal discrepancies in vessel walls
US5957922 *12 Sep 199728 Sep 1999Vidamed, Inc.Transurethral radio frequency apparatus for ablation of the prostate gland and method
US6019757 *7 Jul 19951 Feb 2000Target Therapeutics, Inc.Endoluminal electro-occlusion detection apparatus and method
US602233417 Abr 19988 Feb 2000Vidamed, Inc.Medical probe device with optic viewing capability
US6024733 *22 Nov 199515 Feb 2000Arthrocare CorporationSystem and method for epidermal tissue ablation
US6030379 *22 Sep 199729 Feb 2000Ep Technologies, Inc.Systems and methods for seeking sub-surface temperature conditions during tissue ablation
US6045532 *7 Ago 19984 Abr 2000Arthrocare CorporationSystems and methods for electrosurgical treatment of tissue in the brain and spinal cord
US6045550 *5 May 19984 Abr 2000Cardiac Peacemakers, Inc.Electrode having non-joined thermocouple for providing multiple temperature-sensitive junctions
US6047700 *22 May 199811 Abr 2000Arthrocare CorporationSystems and methods for electrosurgical removal of calcified deposits
US6053172 *22 May 199825 Abr 2000Arthrocare CorporationSystems and methods for electrosurgical sinus surgery
US6063079 *2 Abr 199816 May 2000Arthrocare CorporationMethods for electrosurgical treatment of turbinates
US606308522 Oct 199316 May 2000Scimed Life Systems, Inc.Apparatus and method for sealing vascular punctures
US6066134 *23 Oct 199823 May 2000Arthrocare CorporationMethod for electrosurgical cutting and ablation
US6086585 *18 Ago 199811 Jul 2000Arthrocare CorporationSystem and methods for electrosurgical treatment of sleep obstructive disorders
US6102046 *2 Jun 199815 Ago 2000Arthrocare CorporationSystems and methods for electrosurgical tissue revascularization
US6105581 *14 Nov 199722 Ago 2000Arthocare CorporationElectrosurgical systems and methods for treating the spine
US6109268 *15 Dic 199729 Ago 2000Arthrocare CorporationSystems and methods for electrosurgical endoscopic sinus surgery
US6113597 *14 Nov 19975 Sep 2000Arthrocare CorporationElectrosurgical systems and methods for urological and gynecological procedures
US6117109 *28 Sep 199812 Sep 2000Arthrocare CorporationSystems and methods for electrosurgical incisions on external skin surfaces
US6120499 *3 Ene 199619 Sep 2000Cardima, Inc.Intravascular RF occlusion catheter
US6123702 *10 Sep 199826 Sep 2000Scimed Life Systems, Inc.Systems and methods for controlling power in an electrosurgical probe
US6149620 *12 Feb 199921 Nov 2000Arthrocare CorporationSystem and methods for electrosurgical tissue treatment in the presence of electrically conductive fluid
US6159194 *2 Oct 199712 Dic 2000Arthrocare CorporationSystem and method for electrosurgical tissue contraction
US6159208 *15 Mar 199912 Dic 2000Arthocare CorporationSystem and methods for electrosurgical treatment of obstructive sleep disorders
US6179824 *13 Jun 199730 Ene 2001Arthrocare CorporationSystem and methods for electrosurgical restenosis of body lumens
US617983628 Oct 199830 Ene 2001Arthrocare CorporationPlanar ablation probe for electrosurgical cutting and ablation
US618346810 Sep 19986 Feb 2001Scimed Life Systems, Inc.Systems and methods for controlling power in an electrosurgical probe
US619038121 Ene 199820 Feb 2001Arthrocare CorporationMethods for tissue resection, ablation and aspiration
US619702117 Sep 19986 Mar 2001Ep Technologies, Inc.Systems and methods for controlling tissue ablation using multiple temperature sensing elements
US620354221 Abr 199920 Mar 2001Arthrocare CorporationMethod for electrosurgical treatment of submucosal tissue
US620684717 Mar 199927 Mar 2001Vidamed, Inc.Medical probe device
US621040225 Nov 19973 Abr 2001Arthrocare CorporationMethods for electrosurgical dermatological treatment
US622459227 Jul 19981 May 2001Arthrocare CorporationSystems and methods for electrosurgical tissue treatment in conductive fluid
US622807825 Nov 19978 May 2001Arthrocare CorporationMethods for electrosurgical dermatological treatment
US62280823 Dic 19988 May 2001Arthrocare CorporationSystems and methods for electrosurgical treatment of vascular disorders
US623502010 Abr 199822 May 2001Arthrocare CorporationPower supply and methods for fluid delivery in electrosurgery
US623839111 Jun 199929 May 2001Arthrocare CorporationSystems for tissue resection, ablation and aspiration
US624506510 Sep 199812 Jun 2001Scimed Life Systems, Inc.Systems and methods for controlling power in an electrosurgical probe
US624506820 Ago 199912 Jun 2001Scimed Life Systems, Inc.Resilient radiopaque electrophysiology electrodes and probes including the same
US626465021 May 199924 Jul 2001Arthrocare CorporationMethods for electrosurgical treatment of intervertebral discs
US62646511 Jul 199924 Jul 2001Arthrocare CorporationMethod for electrosurgical spine surgery
US626465218 May 199924 Jul 2001Arthro Care CorporationElectrosurgical systems for treating tissue
US626775828 Ene 199731 Jul 2001Esc Medical Systems Ltd.Apparatus for in situ saphenous vein bypass and less-invasive varicose vein treatment
US627711220 Feb 199821 Ago 2001Arthrocare CorporationMethods for electrosurgical spine surgery
US62839613 Jun 19994 Sep 2001Arthrocare CorporationApparatus for electrosurgical spine surgery
US629663621 Jul 19992 Oct 2001Arthrocare CorporationPower supply and methods for limiting power in electrosurgery
US630938718 May 199930 Oct 2001Arthrocare CorporationSystems and methods for electrosurgical skin resurfacing
US63124085 Dic 19966 Nov 2001Arthrocare CorporationElectrosurgical probe for treating tissue in electrically conductive fluid
US63225496 Ene 200027 Nov 2001Arthocare CorporationSystems and methods for electrosurgical treatment of tissue in the brain and spinal cord
US635503227 Feb 199812 Mar 2002Arthrocare CorporationSystems and methods for selective electrosurgical treatment of body structures
US63639376 May 19982 Abr 2002Arthrocare CorporationSystem and methods for electrosurgical treatment of the digestive system
US638705219 Abr 199314 May 2002Edwards Lifesciences CorporationThermodilution catheter having a safe, flexible heating element
US639102513 Mar 199821 May 2002Arthrocare CorporationElectrosurgical scalpel and methods for tissue cutting
US63949495 Oct 199928 May 2002Scimed Life Systems, Inc.Large area thermal ablation
US639878215 May 19954 Jun 2002Edwards Lifesciences CorporationBipolar vascular sealing apparatus and methods
US641650718 Ene 20009 Jul 2002Arthrocare CorporationMethod for treating articular cartilage defects
US641650815 Feb 20009 Jul 2002Arthrocare CorporationMethods for electrosurgical tissue treatment in conductive fluid
US643210326 Jun 200013 Ago 2002Arthrocare CorporationSystem for electrosurgical treatment of submucosal tissue
US645104428 Dic 199917 Sep 2002Board Of Regents, The University Of Texas SystemMethod and apparatus for heating inflammed tissue
US646135028 Sep 19988 Oct 2002Arthrocare CorporationSystems and methods for electrosurgical-assisted lipectomy
US646135418 May 19998 Oct 2002Arthrocare CorporationSystems for electrosurgical dermatological treatment
US646466127 Mar 200115 Oct 2002Vidamed, Inc.Medical probe with stylets
US646469519 Ene 200115 Oct 2002Arthrocare CorporationMethod for electrosurgical treatment of intervertebral discs
US646827019 Sep 200022 Oct 2002Arthocare CorporationSystem and method for electrosurgical treatment of intervertebral discs
US647515915 Mar 19995 Nov 2002S. Ward CasscellsMethod of detecting vulnerable atherosclerotic plaque
US648220127 Jul 200019 Nov 2002Arthrocare CorporationSystems and methods for tissue resection, ablation and aspiration
US648543021 Feb 199626 Nov 2002Edwards Lifesciences CorporationThermodilution catheter having a safe, flexible heating element
US648867926 Jul 20003 Dic 2002Scimed Life Systems, Inc.Systems and methods for controlling power in an electrosurgical probe
US649488026 Jul 200017 Dic 2002Scimed Life Systems, Inc.Systems and methods for controlling power in an electrosurgical probe
US6500172 *26 Oct 200031 Dic 2002Ep Technologies, Inc.Systems and methods for controlling tissue ablation using multiple temperature sensing elements
US650017318 May 200131 Dic 2002Ronald A. UnderwoodMethods for electrosurgical spine surgery
US651421413 Feb 20014 Feb 2003Scimed Life Systems, Inc.Intravascular temperature sensor
US652977516 Ene 20014 Mar 2003Alsius CorporationSystem and method employing indwelling RF catheter for systemic patient warming by application of dielectric heating
US65407433 Abr 20011 Abr 2003Scimed Life Systems, Inc.Resilient radiopaque electrophysiology electrodes and probes including the same
US65442615 Feb 20018 Abr 2003Arthrocare CorporationSystems and methods for electrosurgical treatment of submucosal tissue
US655755920 Feb 19986 May 2003Arthrocare CorporationElectrosurgical systems and methods with temperature control
US658242320 Abr 199824 Jun 2003Arthrocare CorporationElectrosurgical systems and methods for recanalization of occluded body lumens
US658923719 Ene 20018 Jul 2003Arthrocare Corp.Electrosurgical apparatus and methods for treating tissue
US659599012 May 200022 Jul 2003Arthrocare CorporationSystems and methods for electrosurgical tissue revascularization
US661507125 Jun 19992 Sep 2003Board Of Regents, The University Of Texas SystemMethod and apparatus for detecting vulnerable atherosclerotic plaque
US662015520 Feb 199816 Sep 2003Arthrocare Corp.System and methods for electrosurgical tissue contraction within the spine
US662345423 Jul 199923 Sep 2003Arthrocare Corp.System and method for electrosurgical tissue contraction
US66321935 Ene 200014 Oct 2003Arthrocare CorporationSystems and methods for electrosurgical tissue treatment
US663222012 Nov 199914 Oct 2003Arthrocare Corp.Systems for electrosurgical tissue treatment in conductive fluid
US665910610 Ene 20009 Dic 2003Arthrocare CorporationSystem and methods for electrosurgical treatment of turbinates
US669418112 Feb 200117 Feb 2004Scimed Life Systems, Inc.Methods and devices for detecting vulnerable plaque
US671975410 Abr 200213 Abr 2004Arthrocare CorporationMethods for electrosurgical-assisted lipectomy
US67266848 Nov 200027 Abr 2004Arthrocare CorporationMethods for electrosurgical spine surgery
US674960430 Mar 200015 Jun 2004Arthrocare CorporationElectrosurgical instrument with axially-spaced electrodes
US676326126 Dic 200113 Jul 2004Board Of Regents, The University Of Texas SystemMethod and apparatus for detecting vulnerable atherosclerotic plaque
US676620230 Abr 200220 Jul 2004Arthrocare Corp.Systems and methods for intradermal collagen stimulation
US67700719 Feb 20013 Ago 2004Arthrocare CorporationBladed electrosurgical probe
US677343122 Feb 200110 Ago 2004Arthrocare CorporationMethod for epidermal tissue ablation
US6780177 *27 Ago 200224 Ago 2004Board Of Trustees Of The University Of ArkansasConductive interstitial thermal therapy device
US680513027 Abr 200119 Oct 2004Arthrocare CorporationMethods for electrosurgical tendon vascularization
US68722036 Ene 200329 Mar 2005Board Of Trustees Of The University Of ArkansasConductive interstitial thermal therapy device
US688288519 Mar 200219 Abr 2005Solarant Medical, Inc.Heating method for tissue contraction
US68966748 Nov 200024 May 2005Arthrocare CorporationElectrosurgical apparatus having digestion electrode and methods related thereto
US692964024 Feb 200016 Ago 2005Arthrocare CorporationMethods for electrosurgical tissue contraction within the spine
US693281229 Abr 200223 Ago 2005Scimed Life Systems, Inc.Large area thermal ablation
US697445320 Abr 200113 Dic 2005Arthrocare CorporationDual mode electrosurgical clamping probe and related methods
US699338216 Ago 200231 Ene 2006Board Of Regents The University Of Texas SystemMethod of detecting vulnerable atherosclerotic plaque
US69979264 Feb 200214 Feb 2006Boston Scientific Scimed, Inc.Resistance heated tissue morcellation
US70705963 Oct 20004 Jul 2006Arthrocare CorporationElectrosurgical apparatus having a curved distal section
US7089064 *30 Ago 20028 Ago 2006Ams Research CorporationTherapeutic prostatic thermotherapy
US70936012 Abr 200322 Ago 2006Ams Research CorporationTherapeutic prostatic thermotherapy
US712396830 Abr 199917 Oct 2006The Board Of Regents Of The University Of Texas SystemHeat treatment of inflamed tissue
US71319691 May 20007 Nov 2006Arthrocare CorpSystems and methods for electrosurgical treatment of obstructive sleep disorders
US717925520 Dic 200020 Feb 2007Arthrocare CorporationMethods for targeted electrosurgery on contained herniated discs
US720175018 May 199910 Abr 2007Arthrocare CorporationSystem for treating articular cartilage defects
US725153130 Ene 200431 Jul 2007Ams Research CorporationHeating method for tissue contraction
US725494612 Abr 199514 Ago 2007Edwards Lifesciences CorporationThermodilution catheter having a safe, flexible heating element
US727065810 Mar 200318 Sep 2007Arthrocare CorporationSystems and methods for electrosurgery
US72706615 Feb 200218 Sep 2007Arthocare CorporationElectrosurgical apparatus and methods for treatment and removal of tissue
US72971435 Feb 200420 Nov 2007Arthrocare CorporationTemperature indicating electrosurgical apparatus and methods
US731170221 Ene 200325 Dic 2007Std Manufacturing, Inc.Ablation technology for catheter based delivery systems
US73611733 Ene 200522 Abr 2008Board Of Trustees Of The University Of ArkansasConductive interstitial thermal therapy device
US74225856 Jul 19999 Sep 2008Arthrocare CorporationSystem for electrosurgical myocardial revascularization
US74264095 Ago 200216 Sep 2008Board Of Regents, The University Of Texas SystemMethod and apparatus for detecting vulnerable atherosclerotic plaque
US742926019 Dic 200630 Sep 2008Arthrocare CorporationSystems and methods for electrosurgical tissue contraction within the spine
US742926228 Feb 200130 Sep 2008Arthrocare CorporationApparatus and methods for electrosurgical ablation and resection of target tissue
US743524727 Jun 200214 Oct 2008Arthrocare CorporationSystems and methods for electrosurgical tissue treatment
US744219126 Sep 200128 Oct 2008Arthrocare CorporationSystems and methods for electrosurgical treatment of turbinates
US744561824 Ene 20074 Nov 2008Arthrocare CorporationMethods for tissue ablation using pulsed energy
US74680599 Feb 200723 Dic 2008Arthrocare CorporationSystem and method for epidermal tissue ablation
US749120025 Mar 200517 Feb 2009Arthrocare CorporationMethod for treating obstructive sleep disorder includes removing tissue from base of tongue
US750581216 Jul 199917 Mar 2009Arthrocare CorporationElectrosurgical system for treating restenosis of body lumens
US75072366 Abr 200724 Mar 2009Arthrocare CorporationSystem and method for electrosurgical cutting and ablation
US751387614 Nov 20057 Abr 2009Board Of Regents, The University Of Texas SystemDetecting thermal discrepancies in vessel walls
US75722516 Dic 199911 Ago 2009Arthrocare CorporationSystems and methods for electrosurgical tissue treatment
US758208422 Nov 20021 Sep 2009Boston Scientific Scimed, Inc.Systems and methods for controlling power in an electrosurgical probe
US760316612 Ago 200313 Oct 2009Board Of Regents University Of Texas SystemMethod and apparatus for detection of vulnerable atherosclerotic plaque
US76322676 Jul 200515 Dic 2009Arthrocare CorporationFuse-electrode electrosurgical apparatus
US76911016 Ene 20066 Abr 2010Arthrocare CorporationElectrosurgical method and system for treating foot ulcer
US77042499 May 200527 Abr 2010Arthrocare CorporationApparatus and methods for electrosurgical ablation and resection of target tissue
US774915921 Jun 20056 Jul 2010Boston Scientific Scimed, Inc.Large area thermal ablation
US775853716 Abr 199920 Jul 2010Arthrocare CorporationSystems and methods for electrosurgical removal of the stratum corneum
US77925891 Mar 20057 Sep 2010Ams Research CorporationHeating method for tissue contraction
US779444412 Ago 200314 Sep 2010The Regents Of The University Of CaliforniaCatheter system and methods for delivery of therapeutic cells to cardiac tissue
US779901130 May 200721 Sep 2010The Regents Of The University Of CaliforniaCatheter system and method for delivery of therapeutic compounds to cardiac tissue
US781986317 Nov 200826 Oct 2010Arthrocare CorporationSystem and method for electrosurgical cutting and ablation
US784203118 Nov 200530 Nov 2010Medtronic Cryocath LpBioimpedance measurement system and method
US786256023 Mar 20074 Ene 2011Arthrocare CorporationAblation apparatus having reduced nerve stimulation and related methods
US789223024 Jun 200522 Feb 2011Arthrocare CorporationElectrosurgical device having planar vertical electrode and related methods
US791452525 Abr 200829 Mar 2011Medtronic Cryocath LpBioimpedance measurement system and method
US798868917 Sep 20072 Ago 2011Arthrocare CorporationElectrosurgical apparatus and methods for treatment and removal of tissue
US801215316 Jul 20046 Sep 2011Arthrocare CorporationRotary electrosurgical apparatus and methods thereof
US8104956 *23 Oct 200331 Ene 2012Covidien AgThermocouple measurement circuit
US811407129 May 200714 Feb 2012Arthrocare CorporationHard tissue ablation system
US81924244 Ene 20085 Jun 2012Arthrocare CorporationElectrosurgical system with suction control apparatus, system and method
US824127829 Abr 201114 Ago 2012Covidien AgLaparoscopic apparatus for performing electrosurgical procedures
US825735017 Jun 20094 Sep 2012Arthrocare CorporationMethod and system of an electrosurgical controller with wave-shaping
US826511022 Jun 200911 Sep 2012Board Of Trustees Operating Michigan State UniversityLaser and environmental monitoring method
US826792829 Mar 201118 Sep 2012Covidien AgSystem and method for closed loop monitoring of monopolar electrosurgical apparatus
US826792916 Dic 201118 Sep 2012Covidien AgMethod and system for programming and controlling an electrosurgical generator system
US831778625 Sep 200927 Nov 2012AthroCare CorporationSystem, method and apparatus for electrosurgical instrument with movable suction sheath
US832327925 Sep 20094 Dic 2012Arthocare CorporationSystem, method and apparatus for electrosurgical instrument with movable fluid delivery sheath
US835579912 Dic 200815 Ene 2013Arthrocare CorporationSystems and methods for limiting joint temperature
US836670615 Ago 20085 Feb 2013Cardiodex, Ltd.Systems and methods for puncture closure
US83720679 Dic 200912 Feb 2013Arthrocare CorporationElectrosurgery irrigation primer systems and methods
US837207222 Nov 201112 Feb 2013Cardiodex Ltd.Methods and apparatus for hemostasis following arterial catheterization
US843523621 Nov 20057 May 2013Cardiodex, Ltd.Techniques for heat-treating varicose veins
US84446386 Ene 201221 May 2013Arthrocare CorporationHard tissue ablation system
US847544723 Ago 20122 Jul 2013Covidien AgSystem and method for closed loop monitoring of monopolar electrosurgical apparatus
US848599316 Ene 201216 Jul 2013Covidien AgSwitched resonant ultrasonic power amplifier system
US848606124 Ago 201216 Jul 2013Covidien LpImaginary impedance process monitoring and intelligent shut-off
US856840515 Oct 201029 Oct 2013Arthrocare CorporationElectrosurgical wand and related method and system
US85741879 Mar 20095 Nov 2013Arthrocare CorporationSystem and method of an electrosurgical controller with output RF energy control
US862789722 Ago 201114 Ene 2014Black & Decker Inc.Tiller housing
US86366855 May 200928 Ene 2014Arthrocare CorporationElectrosurgical method and system for treating foot ulcer
US86473404 Ene 201211 Feb 2014Covidien AgThermocouple measurement system
US86631525 May 20094 Mar 2014Arthrocare CorporationElectrosurgical method and system for treating foot ulcer
US86631535 May 20094 Mar 2014Arthrocare CorporationElectrosurgical method and system for treating foot ulcer
US86631545 May 20094 Mar 2014Arthrocare CorporationElectrosurgical method and system for treating foot ulcer
US86632161 Oct 20074 Mar 2014Paul O. DavisonInstrument for electrosurgical tissue treatment
US868501815 Oct 20101 Abr 2014Arthrocare CorporationElectrosurgical wand and related method and system
US869665930 Abr 201015 Abr 2014Arthrocare CorporationElectrosurgical system and method having enhanced temperature measurement
US87473996 Abr 201010 Jun 2014Arthrocare CorporationMethod and system of reduction of low frequency muscle stimulation during electrosurgical procedures
US874740013 Ago 200810 Jun 2014Arthrocare CorporationSystems and methods for screen electrode securement
US874740120 Ene 201110 Jun 2014Arthrocare CorporationSystems and methods for turbinate reduction
US8768485 *27 Nov 20031 Jul 2014Medical Device Innovations LimitedTissue ablation apparatus and method of ablating tissue
US885854516 Ago 201014 Oct 2014Board Of Trustees Of The University Of ArkansasSelective conductive interstitial thermal therapy device
US887086627 Abr 201228 Oct 2014Arthrocare CorporationElectrosurgical system with suction control apparatus, system and method
US887674627 Abr 20094 Nov 2014Arthrocare CorporationElectrosurgical system and method for treating chronic wound tissue
US896698116 Jul 20133 Mar 2015Covidien AgSwitched resonant ultrasonic power amplifier system
US8986322 *14 May 201024 Mar 2015Sabanci UniversitesiApparatus for using hydrodynamic cavitation in medical treatment
US90114281 Mar 201221 Abr 2015Arthrocare CorporationElectrosurgical device with internal digestor electrode
US909535821 Dic 20124 Ago 2015Arthrocare CorporationElectrosurgery irrigation primer systems and methods
US911390031 Ene 201225 Ago 2015Covidien AgMethod and system for controlling output of RF medical generator
US91315972 Feb 20118 Sep 2015Arthrocare CorporationElectrosurgical system and method for treating hard body tissue
US913828227 Jul 201222 Sep 2015Arthrocare CorporationMethod and system of an electrosurgical controller with wave-shaping
US91680829 Feb 201127 Oct 2015Arthrocare CorporationFine dissection electrosurgical device
US916808728 Jul 201027 Oct 2015Arthrocare CorporationElectrosurgical system and method for sterilizing chronic wound tissue
US916808931 Ene 201227 Oct 2015Covidien AgMethod and system for controlling output of RF medical generator
US925416426 Sep 20149 Feb 2016Arthrocare CorporationElectrosurgical system with suction control apparatus, system and method
US925416617 Ene 20139 Feb 2016Arthrocare CorporationSystems and methods for turbinate reduction
US92541679 Dic 20099 Feb 2016Arthrocare CorporationElectrosurgical system and method for sterilizing chronic wound tissue
US927178414 Mar 20131 Mar 2016Arthrocare CorporationFine dissection electrosurgical device
US935806314 Feb 20087 Jun 2016Arthrocare CorporationAblation performance indicator for electrosurgical devices
US943970627 Feb 201413 Sep 2016Medtronic Cryocath LpSystem and method for monitoring bioimpedance and respiration
US94520087 Dic 201227 Sep 2016Arthrocare CorporationSystems and methods for limiting joint temperature
US952655628 Feb 201427 Dic 2016Arthrocare CorporationSystems and methods systems related to electrosurgical wands with screen electrodes
US959714224 Jul 201421 Mar 2017Arthrocare CorporationMethod and system related to electrosurgical procedures
US963616514 Feb 20142 May 2017Covidien LpSystems and methods for measuring tissue impedance through an electrosurgical cable
US96491441 Feb 201616 May 2017Arthrocare CorporationSystems and methods for turbinate reduction
US964914824 Jul 201416 May 2017Arthrocare CorporationElectrosurgical system and method having enhanced arc prevention
US965567014 Feb 201423 May 2017Covidien LpSystems and methods for measuring tissue impedance through an electrosurgical cable
US969381825 Feb 20144 Jul 2017Arthrocare CorporationMethods and systems related to electrosurgical wands
US97134897 Mar 201325 Jul 2017Arthrocare CorporationElectrosurgical methods and systems
US20020077564 *28 Mar 200120 Jun 2002Farallon Medsystems, Inc.Thermography catheter
US20020193785 *14 Ago 200219 Dic 2002Morteza NaghaviMethod and apparatus for heating inflammed tissue
US20030004430 *16 Ago 20022 Ene 2003Casscells S. WardDetecting thermal discrepancies in vessel walls
US20030023238 *30 Ago 200230 Ene 2003Manker Charles F.Therapeutic prostatic thermotherapy
US20030065322 *21 Oct 20023 Abr 2003Dorin PanescuSystems and methods for controlling tissue ablation using multiple temperature sensing elements
US20030171691 *5 Ago 200211 Sep 2003Casscells S. WardMethod and apparatus for detecting vulnerable atherosclerotic plaque
US20030195504 *21 Ene 200316 Oct 2003Tallarida Steven J.Ablation technololgy for catheter based delivery systems
US20030199863 *22 Nov 200223 Oct 2003Swanson David K.Systems and methods for controlling power in an electrosurgical probe
US20040044336 *27 Ago 20024 Mar 2004Gal ShafirsteinConductive interstitial thermal therapy device
US20040044337 *6 Ene 20034 Mar 2004Gal ShafirsteinConductive interstitial thermal therapy device
US20040054335 *12 Ago 200318 Mar 2004Lesh Michael D.Catheter system for delivery of therapeutic compounds to cardiac tissue
US20040073132 *7 May 200315 Abr 2004Tracy MaahsSystems and methods for detecting vulnerable plaque
US20050119645 *3 Ene 20052 Jun 2005Gal ShafirsteinConductive interstitial thermal therapy device
US20050154433 *1 Mar 200514 Jul 2005Solarant Medical, Inc.Heating method for tissue contraction
US20050159727 *15 Mar 200521 Jul 2005Lesh Michael D.Catheter system for delivery of therapeutic compounds to cardiac tissue
US20050171583 *30 Ene 20044 Ago 2005Solarant Medical, Inc.Heating method for tissue contraction
US20050251134 *9 May 200510 Nov 2005Arthrocare CorporationApparatus and methods for electrosurgical ablation and resection of target tissue
US20060020264 *21 Jun 200526 Ene 2006Boston Scientific Scimed, Inc.Large area thermal ablation
US20060094980 *14 Nov 20054 May 2006Casscells S WDetecting thermal discrepancies in vessel walls
US20060155270 *27 Nov 200313 Jul 2006Hancock Christopher PTissue ablation apparatus and method of ablating tissue
US20060167445 *10 Mar 200627 Jul 2006Gal ShafirsteinSelective conductive interstitial thermal therapy device
US20060253117 *9 Mar 20069 Nov 2006Arthrocare CorporationSystems and methods for electrosurgical treatment of obstructive sleep disorders
US20070239134 *30 May 200711 Oct 2007The Regents Of The University Of CaliforniaCatheter system for delivery of therapeutic compounds to cardiac tissue
US20070255162 *18 Nov 20051 Nov 2007Marwan AbboudBioimpedance measurement system and method
US20080125767 *23 Oct 200329 May 2008Sherwood Services AgThermocouple Measurement Circuit
US20080200828 *25 Abr 200821 Ago 2008Cryocath Technologies Inc.Bioimpedance measurement system and method
US20080200829 *25 Abr 200821 Ago 2008Cryocath Technologies Inc.Bioimpedance measurement system and method
US20090131854 *14 Nov 200821 May 2009Boston Scientific Scimed, Inc.Methods and Devices for Thermally Degrading Bacteria and Biofilm
US20100256632 *17 Jun 20107 Oct 2010Boston Scientific Scimed, Inc.Large area thermal ablation
US20130116703 *14 May 20109 May 2013Sabanci UniversitesiApparatus for Using Hydrodynamic Cavitation in Medical Treatment
USD65876015 Oct 20101 May 2012Arthrocare CorporationWound care electrosurgical wand
EP0734228A1 *15 Sep 19932 Oct 1996TAYMOR-LURIA, HowardPercutaneous vascular sealing apparatus and method
EP0734228A4 *15 Sep 199315 May 1996Howard Taymor-LuriaPercutaneous vascular sealing apparatus and method
EP2939629A3 *2 Abr 201524 Feb 2016Cook Medical Technologies LLCAparatus and method for occluding a vessel by rf embolization
WO1993008755A1 *5 Nov 199213 May 1993Ep Technologies, Inc.Ablation electrode with insulated temperature sensing elements
WO1994028809A1 *31 May 199422 Dic 1994Imran Mir ATransurethral radio frequency ablation apparatus
WO1995019148A1 *18 Ene 199520 Jul 1995Endovascular, Inc.Apparatus and method for venous ligation
WO1996032051A1 *3 Abr 199617 Oct 1996Arthrocare CorporationMethods and apparatus for ablation of luminal tissues
WO1999037227A1 *26 Ene 199929 Jul 1999Boston Scientific LimitedTissue resection using resistance heating
Clasificaciones
Clasificación de EE.UU.606/28, 606/31
Clasificación internacionalA61B18/14, A61B18/22, A61B18/08, A61B17/00, A61B18/00, A61B17/22, A61B18/04
Clasificación cooperativaA61B18/082, A61B2018/00767, A61B2018/087, A61B2017/00092, A61B2018/00791, A61B2017/22001, A61B18/22, A61B18/08, A61B2018/00095, A61B2018/00107, A61B2017/00292
Clasificación europeaA61B18/08, A61B18/08B
Eventos legales
FechaCódigoEventoDescripción
23 Ago 1990ASAssignment
Owner name: UNIVERSITY OF KANSAS MEDICAL CENTER, THE, KANSAS
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:MALONE, DAVID G.;VACEK, JAMES L.;SMITH, G. SCOTT;REEL/FRAME:005425/0898;SIGNING DATES FROM 19900815 TO 19900817
20 Sep 1994RFReissue application filed
Effective date: 19931015
17 Abr 1995FPAYFee payment
Year of fee payment: 4